Stone columns are an established method of liquefaction mitigation in clean sands (fines content <15%). Although stone columns are considered less effective in silty soils, an increase in the area replacement ratio or the addition of wick drains may still produce improvement in the normalized blow count. Limited case histories are available with a direct comparison of the use of stone columns with and without wick drains at one location. The Salmon Lake Dam Modification project provided such a scenario. Two test sections were completed at the site prior to construction to determine the area replacement ratio for the final design as well as to compare the application of stone columns with and without wick drains. Visual observations of water and air escaping from wick drains within a distance of 15 ft of the stone column construction confirmed that drains aided in pore pressure dissipation. Test results indicated that stone column treatment with wick drains produced greater improvement in blow count than stone column treatment without drains. For the overall site, there was an increase in improvement ranging from 3 to 8 SPT blow counts. When compared to the results of a similar evaluation of a site in Ogden, Utah, which had a comparable fines content and an area replacement ratio of 26%, the increase in stone column effectiveness produced by adding wick drains was lower at the Salmon Lake Dam site. The increase in improvement at the Ogden, Utah site ranged from 12 to 18 SPT blow counts. At the Ogden site, wick drains were placed between every stone column while they were only placed between vertical rows of columns at Salmon Lake dam. Despite the beneficial effects provided by using wick drains with stone column treatment in silty soils, the performance was below what would be expected for stone column treatment without wick drains in clean sands with less than 15% fines. Stone column treatment also proved less effective in layers of sandy silt than in layers of silty sand, which was indicated by lower average improvement and more points of negative improvement in layers of sandy silt. Although several different area replacement ratios were analyzed (23, 27, 31, and 35%), no consistent trend towards greater improvement in blow count was seen as the replacement ratio increased beyond 23%.

Low slope roofs are roofs with an inclination between 1:16 and 1:4 and have been constructed and preferred for many years due to the benefits they present. The goal of the present work is to study the following problems of low slope roofs, as they are suggested by previous relevant theses and the current needs of the market. Moisture transfer in low slope roofs with constant exposure to high levels of relative humidity. Is protection against corrosion required for steel beams placed directly under the external membranes? If yes, what kind of protection is that? Roof drainage on low slope roofs The study of the first subject was based on simulations of this type of structures in order to see how external moisture affects the moisture level and the potential for corrosion on steel beams. The main goal was to conclude whether we can actually build inverted roofs with steel plates or beams lying right under the roof membrane and what kind of protection is more appropriate to apply, in case it is required. According to the literature review conducted on roof structures, corrosion and corrosion protection, as well as the results of the simulations, the main factor defining the corrosion potential is the indoor environment. Moreover, paint coating seems to be the indicated anticorrosive protection. Regarding drainage, the study focused on the literature review of the current situation, the solutions applied, the existing regulations and guidelines regarding the type of systems used (full flow or gravity, internal or external), the construction of drainage valleys (inclined or horizontal) and the placement and dimensioning of drains and overflows, in order to create a short handbook with issues to be considered by the roof engineer. The main conclusions are that drain valleys are suggested to be constructed completely horizontal, in order to facilitate the cooperation between drains, and that full-flow systems are more efficient than gravity ones and should be preferred, as long as the roof is not exposed to solid material and prone to its accumulation around drains (e.g. roofs covered with vegetation or stone ballast, with overhanging or nearby trees).

No description available.

<p>I denna uppsats undersöks det hur det fungerar med enskilda avlopp utanför kommunens VA-nät. Hur enskilda avlopp är uppbyggda och hur de fungerar. Varför man bör ha avloppsrening, och vilka lagar och regler som styr enskilda avlopp. Jag utreder vidare varför man ska jobba för en ökad rening av avlopp och varför man ska jobba mot att uppnå ett uthålligt samhälle.</p><p>Uppsatsen har en teoridel som handlar om hur och varför vi ska sträva efter en uthållig samhällsutveckling. En strävan som kommuner som Söderköping har när dom försöker få människor att byta till hållbara VA-system.</p><p>Med dom här funderingarna som bakgrund och ett antal frågeställningar har jag skrivit en fyllig bakgrund som går igenom Östersjöns problematik och även relevant information om enskilda avlopp. Jag går igenom varför vi behöver en bra rening och hur man kan jobba för att uppnå en bättre rening. Bakgrunden ger en grund för att jag ska kunna genomföra min undersökning på ett bra sätt.</p><p>I resultat delen undersöker jag hur Söderköpings kommun och Allren arbetar med enskilda avlopp. Jag valde Söderköpings kommun för att det är en kustnära kommun som av den anledningen alltid brottas med att inte få ut läckage av näring i Östersjön. Och det märks att dom har tagit detta ämne på allvar då dom jobbar för att skapa recirkulation av näringen genom exempelvis urinsorterande system.</p><p>I slutet av uppsatsen har jag diskussions delar där jag flätar samman uppsatsen och för en diskussion om vad jag har kommit fram till och vad jag har för åsikter om arbetet med enskilda avlopp.</p><p>Uppsatsen avslutas med att jag har med en didaktik del. En didaktisk del som gör det möjligt att lära ut de kunskaper man besitter efter en uppsats.</p>

In this thesis different mechanical properties for shotcrete (sprayed concrete) such as compression strength, bond strength, bending tensile strength, elastic modulus, free and restrained shrinkage as a function of its age was investigated. One of the main issues was to investigate the difference between ordinary cast concrete and shotcrete. Reliable material data for young and hardening shotcrete is scarce which in the past have made such comparisons difficult. Also, less accurate data representative for cast concrete has often been used in numerical modelling and design analyses. The focus of the project has particularly been on the properties bond strength and restrained shrinkage for which two new testing methods has been developed and evaluated. Microstructural studies have also been performed as a complement to the bond strength testing. The bond to rock is one of the most important properties for shotcrete used as rock reinforcement. During the very first time after spraying the physical properties and the bond to the rock depend on the set accelerator and the micro structure that is formed. The investigation of early age bond strength of shotcrete is of great importance both from a production perspective and a safety perspective. The newly developed method was tested and evaluated and proved that it can be used for bond strength testing already from a couple of hours after shotcreting. The bond, or adhesion, depends on several factors such as texture of the rock, the type of accelerator, application technique, etc. In this work the development of the microstructure in the interfacial transition zone (ITZ) and strength of the bond was investigated. The results show that the bond strength is related to the hydration process, i.e. the strength gain of the shotcrete. The early development of the ITZ was here studied using a scanning electron microscope (SEM) making it possible to observe changes over time, before and after proper cement hydration. Restrained shrinkage cracking of shotcrete, especially in the case of shotcrete sprayed on soft drains that are parts of a tunnel lining not continuously bonded to the rock, can be detrimental for the sustainability of an infrastructure tunnel system. Maintenance and repair costs can be high over time. It is shown that the developed test method realistically captures the behaviour of shotcrete drains on hard rock in situ. The method can be used in the evaluation of different technical solutions for avoiding or minimizing shrinkage cracks in shotcreted soft drains. It can also be used to assess the performance of shotcrete fully bonded to a rock surface, with respect to the ability to prevent cracking or to distribute possible shrinkage damage into several fine cracks instead of one wide. / <p>QC 20140526</p>

Waste, that is any matter whether gaseous, liquid or solid or any combination thereof, originating from any residential, commercial or industrial area identified as undesirable or superfluous by-product, emission, residue or remainder of any process or activity tends to be a hazard to the environment. Waste is generated in all processes which transform materials from one state, form or medium to another. The management of waste in the Sedibeng District Municipality is a very complex problem. There are many reasons for this and these include: the diverse and voluminous waste stream; progressive accumulation of waste in the environment; large numbers of unpermitted waste disposal sites; the severe shortage of hazardous waste disposal sites and shortage of personnel in local municipalities qualified to implement existing legislation. The accumulation of waste in the district not only poses a serious and growing threat to health and quality of life, but also causes infrastructural damage such as the blocking of storm water drains and sewer by litter which ultimately leads to costly road and pavement destruction and increase in maintenance costs. The objective of the study was to investigate waste management activities in the Sedibeng District Municipality and to explore best practices as strategies for recommendations. The Sedibeng District Municipality comprises three local municipalities namely the Emfuleni, Lesedi and Midvaal Local Municipalities. Due to the fact that the Municipality forms part of the industrial hub of the Gauteng Province, there has been an excessive influx of the people into the district and, as a result, more houses had to be built and more normal urban services such as electricity, sanitation, water and waste, had to be provided. The study intended to investigate different waste management strategies that are employed by the three local municipalities that could help reduce the impacts and volumes of waste that are generated by residents before such waste could pollute the environment. A further objective was to explore possible waste reduction mechanisms such as recycling that can help reduce waste volumes before they reach the disposal site. Arising from the problem statement on waste management for this study, it is important that the locus of this study be directed towards the solution of the problem on waste management activities in the Sedibeng District Municipality The following hypothesis was accordingly formulated: Waste management strategies and practices as currently practised in the Sedibeng District Municipality are obsolete, outdated and inadequate to attain a cleaner environment and as a result, there is a need to explore the development of more cost effective strategies in waste management. Comparative study of the different strategies that are employed in the three local municipalities as well as the challenges they face when providing the required service, were made. Similar study was applied to the achievements that are recorded as findings of the study. The challenges and success stories highlighted in the study were found through the use of questionnaires that were distributed to respondents in the three local municipalities. Questionnaires for the study were compiled for both councilors and municipal officials. The research instruments for the study included questionnaires, interviews and consultations with members of the community. Further technique was participant observation, the researcher being responsible for the provision of refuse removal services to the Evaton and Sebokeng communities. Amongst others, it was found that: discrepancies existed in the waste management processes and these include the following: • There was a serious problem of personnel shortage in municipalities as a result of financial constraints that led to nonreplacement of personnel who went on retirement, resigned or died; • Existing equipment do not compliment the growing population figures as well as the sizes of the municipality and as a result, residents opted to dump waste at their backyards as an alternative procedure for disposal of waste from their homes, and • Problems attributed to illegal dumping increase each day and their resolution will be a function of implementation of compliance with legislation. • Community awareness of refuse collection schedule is at minimum, a situation which leads to illegal dumping of waste, and • Tariff on refuse removal is deemed to be prohibitive to African residential areas. The study ends with recommendations for management action on waste, and for further research. / Thesis (Ph.D. (Public Management and Administration))--North-West University, Vaal Triangle Campus, 2010.

Waste, that is any matter whether gaseous, liquid or solid or any combination thereof, originating from any residential, commercial or industrial area identified as undesirable or superfluous by-product, emission, residue or remainder of any process or activity tends to be a hazard to the environment. Waste is generated in all processes which transform materials from one state, form or medium to another. The management of waste in the Sedibeng District Municipality is a very complex problem. There are many reasons for this and these include: the diverse and voluminous waste stream; progressive accumulation of waste in the environment; large numbers of unpermitted waste disposal sites; the severe shortage of hazardous waste disposal sites and shortage of personnel in local municipalities qualified to implement existing legislation. The accumulation of waste in the district not only poses a serious and growing threat to health and quality of life, but also causes infrastructural damage such as the blocking of storm water drains and sewer by litter which ultimately leads to costly road and pavement destruction and increase in maintenance costs. The objective of the study was to investigate waste management activities in the Sedibeng District Municipality and to explore best practices as strategies for recommendations. The Sedibeng District Municipality comprises three local municipalities namely the Emfuleni, Lesedi and Midvaal Local Municipalities. Due to the fact that the Municipality forms part of the industrial hub of the Gauteng Province, there has been an excessive influx of the people into the district and, as a result, more houses had to be built and more normal urban services such as electricity, sanitation, water and waste, had to be provided. The study intended to investigate different waste management strategies that are employed by the three local municipalities that could help reduce the impacts and volumes of waste that are generated by residents before such waste could pollute the environment. A further objective was to explore possible waste reduction mechanisms such as recycling that can help reduce waste volumes before they reach the disposal site. Arising from the problem statement on waste management for this study, it is important that the locus of this study be directed towards the solution of the problem on waste management activities in the Sedibeng District Municipality The following hypothesis was accordingly formulated: Waste management strategies and practices as currently practised in the Sedibeng District Municipality are obsolete, outdated and inadequate to attain a cleaner environment and as a result, there is a need to explore the development of more cost effective strategies in waste management. Comparative study of the different strategies that are employed in the three local municipalities as well as the challenges they face when providing the required service, were made. Similar study was applied to the achievements that are recorded as findings of the study. The challenges and success stories highlighted in the study were found through the use of questionnaires that were distributed to respondents in the three local municipalities. Questionnaires for the study were compiled for both councilors and municipal officials. The research instruments for the study included questionnaires, interviews and consultations with members of the community. Further technique was participant observation, the researcher being responsible for the provision of refuse removal services to the Evaton and Sebokeng communities. Amongst others, it was found that: discrepancies existed in the waste management processes and these include the following: • There was a serious problem of personnel shortage in municipalities as a result of financial constraints that led to nonreplacement of personnel who went on retirement, resigned or died; • Existing equipment do not compliment the growing population figures as well as the sizes of the municipality and as a result, residents opted to dump waste at their backyards as an alternative procedure for disposal of waste from their homes, and • Problems attributed to illegal dumping increase each day and their resolution will be a function of implementation of compliance with legislation. • Community awareness of refuse collection schedule is at minimum, a situation which leads to illegal dumping of waste, and • Tariff on refuse removal is deemed to be prohibitive to African residential areas. The study ends with recommendations for management action on waste, and for further research. / Thesis (Ph.D. (Public Management and Administration))--North-West University, Vaal Triangle Campus, 2010.

I denna uppsats undersöks det hur det fungerar med enskilda avlopp utanför kommunens VA-nät. Hur enskilda avlopp är uppbyggda och hur de fungerar. Varför man bör ha avloppsrening, och vilka lagar och regler som styr enskilda avlopp. Jag utreder vidare varför man ska jobba för en ökad rening av avlopp och varför man ska jobba mot att uppnå ett uthålligt samhälle. Uppsatsen har en teoridel som handlar om hur och varför vi ska sträva efter en uthållig samhällsutveckling. En strävan som kommuner som Söderköping har när dom försöker få människor att byta till hållbara VA-system. Med dom här funderingarna som bakgrund och ett antal frågeställningar har jag skrivit en fyllig bakgrund som går igenom Östersjöns problematik och även relevant information om enskilda avlopp. Jag går igenom varför vi behöver en bra rening och hur man kan jobba för att uppnå en bättre rening. Bakgrunden ger en grund för att jag ska kunna genomföra min undersökning på ett bra sätt. I resultat delen undersöker jag hur Söderköpings kommun och Allren arbetar med enskilda avlopp. Jag valde Söderköpings kommun för att det är en kustnära kommun som av den anledningen alltid brottas med att inte få ut läckage av näring i Östersjön. Och det märks att dom har tagit detta ämne på allvar då dom jobbar för att skapa recirkulation av näringen genom exempelvis urinsorterande system. I slutet av uppsatsen har jag diskussions delar där jag flätar samman uppsatsen och för en diskussion om vad jag har kommit fram till och vad jag har för åsikter om arbetet med enskilda avlopp. Uppsatsen avslutas med att jag har med en didaktik del. En didaktisk del som gör det möjligt att lära ut de kunskaper man besitter efter en uppsats.

The topic of my thesis is to study the complex reconstruction of the locomotive servicing depot Praha Liben. The locomotive depot is both operational maintenance and repair trains. The section reconstruction begins in turnout number 1, the whole area locomotive depot will be reconstructed. The main task is to propose an exchange of stepped old construction turnout for turnout new one in the whole area of the depot. The total number of changed points is 27. Depot demolition tasks in order to extend the track number 10 on the minimum usable effective length of 105 meters is the other task. Establishment of two dead-end tracks number 15 and 17 will be extend to an effective length of 105 metres. Retaining wall with PU componentsis designed along track 17. The next task is to solve the drainage area. The area will be drained interconnected system drains into the sewer and trench walls.

[pt] A história registra ao longo dos séculos muitos casos de colapso de depósitos de solos arenosos, com consideráveis prejuízos econômicos, perdas de vidas humanas e danos ao meio ambiente, causados pela liquefação dinâmica ou por mobilidade cíclica. Quando um desempenho satisfatório de estruturas não puder ser garantido sob carregamento sísmico, métodos de mitigação devem ser empregados para reduzir o potencial de liquefação. Dentre estes, a execução de drenos verticais é solução interessante, mas desafiadora, pois drenos verticais podem ser utilizados caso dissipem suficientemente rápido os excessos de poropressão e transportem eficientemente o volume de água durante os poucos segundos de duração de terremotos. Uma dificuldade é a avaliação do coeficiente de permeabilidade do depósito de solo, o que afeta e torna incerta a distância desejável entre drenos. Nesta dissertação, análises do desempenho de drenos verticais para mitigação de liquefação dinâmica são realizadas com base em formulações matemáticas e modelos numéricos pelo método dos elementos finitos. / [en] Throughout centuries there are many recorded cases of collapse of sandy deposits with considerable economic losses, loss of human life and damage to the environment caused by the dynamic liquefaction or cyclic mobility. When a satisfactory performance of structures can’t be guaranteed under seismic loading, methods of mitigation must be employed in order to reduce the potential of liquefaction. Among these methods, the execution of prefabricated vertical drains is an interesting, but challenging, solution, because drains can be used if they dissipate very quickly the excess of porepressure generated during the small duration of earthquakes. One of the main challenges is to evaluate the coefficient of permeability of the deposit which affects and brings uncertainties to the desirable distance between the drains installed. On this work, analysis of the performance of vertical drains to mitigate dynamic liquefaction are performed based in mathematical formulations and numerical models through the Finite Element Method.